The Illinois based company launched proceedings in London’s Technology and Construction Court this summer. NHS England has denied the allegation.

Last January, NHS chiefs called on the pharmaceutical industry to “work with us” to help eliminate hepatitis C by 2025 – five years earlier than the World Health Organisation’s target.

The procurement, described by NHS England as the single largest medicines procurement ever done by the NHS, was launched in spring. Its estimated value is in the hundreds of millions of pounds.

At the time, NHS England said it hoped the procurement would lead to new treatments being offered to patients by October.

The procurement was launched in a bid to lower the cost of hepatitis C drugs, which are manufactured by Abbvie, Gilead Sciences and MSD Pharmaceutical.

Successful companies would be given three year contracts, with NHS England having an option to extend them by two further years.

According to court documents, which are heavily redacted due to commercial sensitivity, Abbvie alleged NHS England breached its duty to treat all bidders fairly.

But NHS England said the allegation was “embarrassing for lack of particulars”.

A spokesman for the regulator told HSJ the procurement process was “continuing despite one manufacturer challenging an aspect of the competition”.

Asked if the challenge had caused delay to the programme’s October rollout target, the spokesman said NHS England could not answer due to “legal reasons”.

But Steve Ryder of the British Liver Trust said stakeholders had previously been told the rollout had been delayed until at least January, though NHS England had not specified what had caused the delay.

While stressing he did not know the details of the procurement process, Dr Ryder said: “Our concerns would be if this will delay implementation further.”

He said he was not surprised a challenge had been made, given the uniqueness and complexity of the procurement.

Currently, both NHS England and Abbvie are preparing for a trial, for which a date has not yet been made public.

The case has so far been heard in private, but confidentiality restrictions were lifted by Mr Justice Fraser in the autumn.

An Abbvie spokeswoman said: “Abbvie has entered into legal action against NHS England. We cannot comment any further as the legal proceedings are not yet concluded.”

Hepatitis C is a virus that infects the liver. Usually spread through blood to blood contact, the virus can cause life-threatening damage to the liver over many years. With modern treatments, it is usually possible to cure the infection.

Health chiefs estimate more than 160,000 people in England live with the disease.